Exam Professional Data Engineer topic 1 question 256 discussion

- Enable Airflow REST API: In Cloud Composer, enable the "Airflow web server" option. - Set Up Cloud Storage Notifications: Create a notification for new files, routing to a Cloud Function. - Create PSC Endpoint: Establish a PSC endpoint for Cloud Composer. - Write Cloud Function: Code the function to use the Airflow REST API (via PSC endpoint) to trigger the DAG. ======== Why not Option D - Using the web server URL directly wouldn't work without internet access or a direct path to the web server.

This is A, as steve_pegleg says, there is no way to connect the cloud function to the Airflow instance, without first enabling private access. The pubsub pattern makes sense in this context.

This is the guidance how to use method in A: https://cloud.google.com/composer/docs/composer-2/triggering-gcf-pubsub "In this specific example, you create a Cloud Function and deploy two DAGs. The first DAG pulls Pub/Sub messages and triggers the second DAG according to the Pub/Sub message content." For C & D, this guidance says it can't be done when you have Private or VPS Service Controls set up: https://cloud.google.com/composer/docs/composer-2/triggering-with-gcf#check_your_environments_networking_configuration "This solution does not work in Private IP and VPC Service Controls configurations because it is not possible to configure connectivity from Cloud Functions to the Airflow web server in these configurations."

C is not correct because "this solution does not work in Private IP and VPC Service Controls configurations because it is not possible to configure connectivity from Cloud Functions to the Airflow web server in these configurations". https://cloud.google.com/composer/docs/how-to/using/triggering-with-gcf The correct answer is A using Pub/Sub https://cloud.google.com/composer/docs/composer-2/triggering-gcf-pubsub

Why not Option C? C involves creating a Private Service Connect (PSC) endpoint, which, while viable for creating private connections to Google services, adds complexity and might not be required when simpler solutions like VPC Serverless Access (as in Option D) can suffice.

The answer should be D Serverless VPC Access makes it possible for you to connect directly to your Virtual Private Cloud (VPC) network from serverless environments such as Cloud Run, App Engine, or Cloud Functions. Configuring Serverless VPC Access allows your serverless environment to send requests to your VPC network by using internal DNS and internal IP addresses (as defined by RFC 1918 and RFC 6598). The responses to these requests also use your internal network. You can use Serverless VPC Access to access Compute Engine VM instances, Memorystore instances, and any other resources with internal DNS or internal IP address. (Reference: https://cloud.google.com/vpc/docs/serverless-vpc-access) When you use Airflow Rest API to tigger the job, the url is based on the private IP address of Cloud Composer Instance, so you need to use Serverless VPC Access for it.

Option C, raaad explained well why

C. 1. Enable the Airflow REST API, and set up Cloud Storage notifications to trigger a Cloud Function instance. 2. Create a Private Service Connect (PSC) endpoint. 3. Write a Cloud Function that connects to the Cloud Composer cluster through the PSC endpoint.